The Children's Hospital of Philadelphia (CHOP) General Clinical Research Center (GCRC) has been continuously funded, since its inception in 1965. Since the last application, GCRC investigators have continued to be productive scientifically, and utilization of outpatient and inpatient facilities has increased- The present application contains 39 protocols from 31 investigators, 26 from the Department of Pediatrics and five from other Departments of the University of Pennsylvania Schools of Medicine and Nursing. These projects explore a wide range of pediatric diseases including metabolic and genetic disorders (sickle cell disease, diabetes, hyperinsulinism, galactosemia, familial hypercholesterolemia ornithine transcarbamylase deficiency, Velocardiofacial Syndrome, Alagille Syndrome); pediatric AIDS (clinical trials of antiretroviral therapy vaccines, and immunotherapy); and diseases of the newborn (respiratory distress syndrome, necrotizing enterocolitis, retinopathy of prematurity, apnea). Nutritional studies (growth failure in sickle cell disease, dietary intake and cardiovascular risk factors, infant feeding behavior and obesity) are another major scientific focus of the GCRC. Human gene therapy is likely to become an inceasingly important component of GCRC activity. New training programs have been established, and a new Clinical Associate Physician award is anticipated. Current specialized resources of the GCRC include: Core Laboratory, Neonatal Scatterbed Program, and Dietary Services. The present application proposes to augment the resources available to investigators through expansion of laboratory, biostatistical, and nutrition research services, and creation of a CDMAS facility at CHOP. With new leadership in place, strong institutional support, and enhanced facilities in the near future, the GCRC is well- positioned to provide investigations with the resources needed to study basic mechanisms of pediatric diseases and new forms of therapy, many of which involve emerging technologies.